Browsing by Author "Tung, Wei-Lin"

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A Multifunctional Nanodevice Capable of Imaging, Magnetically Controlling, and In Situ Monitoring Drug Release
(2009-11-09)
Hu, Shang-Hsiu
;
Kuo, Kuan-Ting
;
Tung, Wei-Lin
;
Liu, Dean-Mo
;
Chen, San-Yuan
The multifunctional nanodevice described here integrates nanoscaled imaging, targeting, and controlled drug delivery, as well as the capability to monitor, in situ, the amount of drug released from the nanodevice with single-cell resolution. The nanodevice is composed of a polymer core/single-crystal iron oxide shell nanostructure bonded to a quantum dot. It shows outstanding release and retention characteristics via an external on/off manipulation of a high-frequency magnetic field. Upon magnetic stimulation, the single-crystal iron oxide shell demonstrates formation of nanometer-sized polycrystal domains of varying orientation. This allows a variation between retention and slow release of the drug. Further stimulation causes permanent rupturing of the shell, causing release of the drug in a burst-like manner. The quantum dot bonded to the nanodevice provides optical information for in situ monitoring of the drug release through use of a magnetic field. Remote control drug release from the nanodevice in a cancerous cell line (HeLa) was successfully accomplished using the same induction scenario. When nanodevices equipped with quantum dots are taken into cancerous cells, they are able to provide real-time drug dose information through a corresponding variation in emission spectrum. The nanodevice designed in this study has achieved its potential as a cell-based drug-delivery system for therapeutic applications.
Bioactive TiO2 ultrathin film with worm-like mesoporosity for controlled drug delivery
(2012-04-01)
Chao, Chih-Shin
;
Liu, Kun-Ho
;
Tung, Wei-Lin
;
Chen, San-Yuan
;
Liu, Dean-Mo
Ultrathin mesoporous TiO2 coatings with a wormhole-like architecture were synthesized using evaporation-induced self-assembly method. The morphological and chemical structures of TiO2 films were characterized using small-angle and large-angle X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transformed infrared spectrometry (FTIR). The films demonstrated a thickness of similar to 120 nm and open-porous nanostructure. By taking advantage of the tortuosity of the worm-like mesoporous architecture associated with the chemistry of the TiO2 film, a sustained drug release using ibuprofen and vancomycin as model molecules from the film was determined. Besides, adhesion behavior of osteoblast cells, together with an in vitro apaptitic formation substantiated the cytocompatibility and bioactivity of the mesoporous TiO2 films. Such combined bioactive and drug-releasing functions of the TiO2 films with worm-like mesoporosity ensure an improved therapeutic performance for potential applications included orthopedics, dentistry, and drug delivery. (C) 2011 Elsevier Inc. All rights reserved.
Surfactant-Free, Self-Assembled PVA-Iron Oxide/Silica Core-Shell Nanocarriers for Highly Sensitive, Magnetically Controlled Drug Release and Ultrahigh Cancer Cell Uptake Efficiency
(2008-10-09)
Hu, Shang-Hsiu
;
Liu, Dean-Mo
;
Tung, Wei-Lin
;
Liao, Chen-Fu
;
Chen, San-Yuan
Surfactant-free, self-assembled iron oxide/silica core-shell (SAIO@SiO2) nanocarriers were synthesized as bifunctional magnetic vectors that can be triggered for the controlled release of therapeutic agents by an external magnetic field. In addition, drug release profiles can be well-regulated through an ultrathin layer of silica shell. The hydrophobic drug molecules were encapsulated within the iron oxide-PVA core and then further covered with a thin-layer silica shell to regulate the release pattern. Remote control of drug release from the SAIO@SiO2 nanocarriers was achieved successfully using an external magnetic field where the core phase being structurally disintegrated to a certain extent while subjected to magnetic stimulus, resulting in a burst release of the encapsulated drug. However, a relatively slow and linear release restored immediately, directly after removal of the stimulus. The nanostructural evolution of the nanocarriers upon the stimulus was examined and the mechanism for controlled drug release is proposed for such a core-shell nanocarrier. Surprisingly, the surfactant-free SAIO@SiO2 nanocarriers demonstrated a relatively high uptake efficiency from the HeLa cell line. Together with a well-regulated controlled release design, the nanocarriers may provide great advantages as an effective cell-based drug delivery nanosystem for biomedical applications.
Use of Irinotecan for Treatment of Small Cell Carcinoma of the Prostate
(2011-05-15)
Tung, Wei-Lin
;
Wang, Yuwei
;
Gout, Peter W.
;
Liu, Dean-Mo
;
Gleave, Martin
BACKGROUND. Prostatic small cell carcinoma (SCC) is a rare variant of prostate cancer. It is extremely aggressive and resistant to available therapies with a median survival range of 5-17 months. No standard chemotherapeutic regimen has been established for its treatment. In search of a new therapeutic approach, we examined the response of patient-derived prostatic SCC tissue xenografts to irinotecan, a topoisomerase I inhibitor. METHODS. A tumor tissue line was established from a patient's prostatic SCC by subrenal capsule grafting using NOD-SCID mice. Mice carrying subcutaneous transplants of the tumor line were then treated for 2 weeks with irinotecan alone and in combination with cisplatin. The effect on tumor volume, histopathology, and apoptosis were determined. RESULTS. The prostatic SCC tissue line resembled the donor tissue in morphologic and immunohistochemical features. Irinotecan (20 mg/kg/day; days 1-3, 8-10) completely arrested xenograft growth with a small reduction in tumor volume and only minor weight loss of the hosts (7%); irinotecan (12 mg/kg; same schedule) + cisplatin (2.5 mg/kg/day; days 1 and 8) had a similar effect, but with lower weight loss. While the growth inhibition involved apoptosis, it was also associated with a marked increase in autophagy. CONCLUSIONS. Tumor tissue lines established via subrenal capsule xenografting provide models with clinical relevance and the present study suggests that irinotecan could be useful for therapy of refractory prostatic SCC, in particular in combination with cisplatin. Prostate 71: 675-681, 2011. (C) 2010 Wiley-Liss, Inc.